On Wed, 24 Oct 2012 11:28:58 +1300 IVP wrote: > Any other ideas or experiences ? I keep daydreaming about cameras > but I don't think that's necessary, and I want to use components that > are cheap and repeatedly available. Even something like an optical > mouse sensor perhaps. Cheap enough to scavenge from a bought one > or pick up as broken I think you'll be better off with a camera. In fact the only drawback I can think of is speed. The camera will give you only tens of images per second. On the other hand, even a cheap camera could give you a much faster 'prescan' of the drawing and quickly detect where the actual drawing=20 is, so you could skip white areas. Even a cheap webcam with bad optics would work, as long as you use the same reference point for the precision scan. John --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .